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Approximation algorithm for minimizing relay node placement in wireless sensor networks

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science china(Information sciences) 2010年第11期53卷 2332-2342页

作者： LU KeZhong1,2, CHEN GuoLiang1,2, FENG YuHong1,2, LIU Gang1,2 & MAO Rui1,2 1College of Computer science and Software Engineering, shenzhen university, shenzhen 51.060, china 2National High Performance computing Center at shenzhen, shenzhen 51.060, china 1. College of Computer science and Software Engineering Shenzhen University Shenzhen 518060 China2. National High Performance Computing Center at Shenzhen Shenzhen 518060 China

To eliminate the routing load unbalance among sensor nodes, one approach is to deploy a small number of powerful relay nodes acting as routing nodes in wireless sensor networks, the major optimization objective of which is to minimize the number of relay nodes required. In this paper, we prove that the relay node placement problem in a bounded plane is a P problem, but its computational complexity in general case is quite great. From the geometric cover feature of the relay node placement problem, an O(n2 log n) time greedy approximation algorithm is proposed, where n is the number of sensor nodes. Particularly, at each stage of this algorithm's iterative process, we first select a critical node from uncovered sensor nodes, and then determine the location of relay node based on the principle of preferring to cover the sensor node closer to the critical node, so as to prevent the emergence of isolated node. Experiment results indicate that our proposed algorithm can generate a near optimum feasible relay node deployment in a very short time, and it outperforms existing algorithms in terms of both the size of relay node deployment and the execution time.

关键词： wireless sensor network relay node placement geometrical cover approximation algorithm greedy algorithm

THz-TDS signal analysis and substance identification via the conformal split

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science china(Information sciences) 2012年第1期55卷 49-63页

作者： XIE WeiXin1,2,LI Jing1,2&PEI JiHong2 1School of Electronic Engineering,Xidian university,Xi'an 710071,china 2intelligent Information Institute,shenzhen university,shenzhen 51.060,china 1. School of Electronic Engineering Xidian University Xi’an 710071 China2. Intelligent Information Institute Shenzhen University Shenzhen 518060 China

A terahertz time-domain spectroscopy(THz-TDS)imaging system can obtain high-dimensional signals with substance fingerprint *** introducing geometric algebra,a novel signal analysis approach to THz-TDS signals is developed based on an optical physical *** this approach,signals are represented with vectors in the high-dimensional real vector *** distribution properties and algebraic relationships of THz-TDS signals are *** is proved that every complex refractive index of substances relates to a unique 2-blade,the vectors corresponding to the samples of the same substance are collinear and belong to the intrinsic 2-blade of the *** decomposed through the conformal split with respect to a 2-blade,THz-TDS signals of high dimensionality can be related to vectors in a 2-dimensional *** on the conformal split properties we deduced,two criteria for substance identification on the basis of THz-TDS signals are ***,a novel substance identification method via the conformal split is *** the method,the 2-blade related to each "known" substance is calculated with two vectors corresponding to THz-TDS signals measured from samples of the substance but with dierent *** the conformal split with respect to those 2-blades,an identified vector corresponding to a THz-TDS signal is linearly related to the vector in a 2-dimensional *** substance of a sample can be identified using criteria on the projected vectors in the *** method can contribute to accurate classification and ***,two experiments are presented that show the feasibility and accuracy of this method.

关键词： terahertz time-domain spectroscopy substance identification geometric algebra conformal split

Power minimization with derivative constraints for high dynamic GPS interference suppression

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science china(Information sciences) 2012年第4期55卷 857-866页

作者： WU RenBiao 1,2,LI Chan 1 & LU Dan 1 1 Tianjin Key Laboratory for Advanced Signal Processing,Civil Aviation university of china,Tianjin 300300,china 2 intelligent Information Institute of ATR Lab,shenzhen university,shenzhen,51.060,china 1. Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin 300300 China2. Intelligent Information Institute of ATR Lab Shenzhen University Shenzhen 518060 China

In this paper,a novel adaptive interference suppression algorithm is proposed for high dynamic GPS (global positioning system) *** new method incorporates derivative constraints on the inter-ference DOA (direction of arrival) into power minimization approach,which could broaden the width of nulls in the interferences directions and adapt to the rapid change of the interference *** with the traditional wide nulling algorithm based on the derivative constraints,the new method does not have to know or estimate the DOAs of the desired signal and the *** new method is firstly discussed in the context of spatial processing,and then extended to space-time adaptive processing to mitigate wideband diffusive multipath *** of the new method is verified via simulation examples.

关键词： GPS interference cancellation adaptive arrays space-time adaptive processing high dynamic GPS receiver

A novel STAP method for the detection of fast air moving targets from high speed platform

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science china(Information sciences) 2012年第6期55卷 1259-1269页

作者： WU RenBiao 1,2,JIA QiongQiong 1 & LI Hai 1 1 Tianjin Key Laboratory for Advanced Signal Processing,Civil Aviation university of china,Tianjin 300300,china 2 intelligent Information Institute of ATR Lab,shenzhen university,shenzhen 51.060,china 1. Tianjin Key Laboratory for Advanced Signal Processing Civil Aviation University of China Tianjin 300300 China2. Intelligent Information Institute of ATR Lab Shenzhen University Shenzhen 518060 China

Space-time adaptive processing (STAP) is an effective method for detecting moving target in airborne/spaceborne ***,the detection of fast air moving targets from high speed platform is challenged by the range walk of both the clutter and moving *** is well known that keystone formatting can be used to compensate for the range walk of multiple moving targets simultaneously without using the knowledge of the motion ***,in the presence of serious Doppler ambiguity of fast air moving targets,distribution of the clutter will be affected by the keystone formatting matched to the ambiguity number of targets,and as a result the STAP performance will *** this paper,a novel STAP method is proposed for the detection of fast air moving targets from high speed platform,which can deal with the range walk of both clutter and *** of the new method is verified via simulation examples.

关键词： airborne/spaceborne radar keystone formatting space-time adaptive processing (STAP) moving target detection

Tissue P systems with cell separation: attacking the partition problem

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science china(Information sciences) 2011年第2期54卷 293-304页

作者： ZHANG XingYi1, WANG Shuo2, NIU YunYun2 & PAN LinQiang2 1Key Lab of intelligent computing and Signal Processing of Ministry of Education, School of Computer science and Technology, Anhui university, Hefei 230039, china 2Image Processing and intelligent Control Key Laboratory of Education Ministry of china, Department of Control science and Engineering, Huazhong university of science and Technology, Wuhan 430074, china 1. Key Lab of intelligent computing and Signal Processing of Ministry of Education School of Computer Science and Technology Anhui University Hefei 230039 China2. Image Processing and Intelligent Control Key Laboratory of Education Ministry of China Department of Control Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China

Tissue P systems are distributed parallel and non-deterministic computing models in the framework of membrane computing, which are inspired by intercellular communication and cooperation between neurons. Recently, cell separation is introduced into tissue P systems, which enables systems to generate an exponential workspace in a polynomial time. In this work, the computational power of tissue P systems with cell separation is investigated. Specifically, a uniform family of tissue P systems with cell separation is constructed for effciently solving a well-known NP-complete problem, the partition problem.

关键词： membrane computing tissue P system cell separation partition problem

Simulation study of phase retrieval for hard X-ray in-line phase contrast imaging

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science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 450-458页

作者： YU Bin1,2, PENG Xiang1,2, TIAN Jindong1, NIU Hanben1, DIAO Luhong3 & LI Hua3 1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Institute of Optoelec- tronics, shenzhen university, shenzhen 51.060, china 2. State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin university, Tianjin 300072,china 3. Key Laboratory of intelligent Information Processing, Institute of computing Technology, Chinese Academy of sciences, Beijing 100080,china 1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education Institute of Optoelectronics Shenzhen University 518060 Shenzhen China 2. State Key Laboratory of Precision Measuring Technology and Instruments Tianjin University 300072 Tianjin China 3. Key Laboratory of intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences 100080 Beijing China

Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.

关键词： X-ray optics, phase contrast imaging, phase retrieval, angular spectrum, hard X-ray.

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DWT BASED HMM FOR FACE RECOGNITION

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Journal of Electronics(china) 2007年第6期24卷 835-837页

作者： Shen Linlin Ji Zhen Bai Li Xu Chen TI DSPs Lab Faculty of Information Engineering Shenzhen University Shenzhen 518050 China School of Computer science ＆ Information Technology University of Nottingham NG8 1BB UK Institute of intelligent computing science Shenzhen University Shenzhen 518060 China

A novel Discrete Wavelet Transform (DWT) based Hidden Markov Module (HMM) for face recognition is presented in this letter. To improve the accuracy of HMM based face recognition algorithm, DWT is used to replace Discrete Cosine Transform (DCT) for observation sequence ex- traction. Extensive experiments are conducted on two public databases and the results show that the proposed method can improve the accuracy significantly, especially when the face database is large and only few training images are available.

关键词： Discrete Wavelet Transform (DWT) Hidden Markov Model (HMM) Face recognition

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Reverse extraction of early-age hydration kinetic equation from observed data of Portland cement

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science china(Technological sciences) 2010年第6期53卷 1540-1553页

作者： WANG Lin1,YANG Bo2,ZHAO XiuYang1,2,CHEN YueHui2 & CHANG Jun3 1 School of Computer science and Technology,Shandong university,Jinan 250101,china 2 Provincial Key Laboratory for Network-based intelligent computing,university of Jinan,Jinan 250022,china 3 School of Material science and Engineering,university of Jinan,Jinan 250022,china 1. School of Computer science and Technology Shandong University Jinan 250101 China2. Provincial Key Laboratory for Network-based Intelligent Computing University of Jinan Jinan 250022 China3. School of Material Science and Engineering University of Jinan Jinan 250022 China

The early-age hydration of Portland cement paste has an important impact on the formation of microstructure and development of ***,manual derivation of hydration kinetic equation is very difficult because there are multi-phased,multi-sized and interrelated complex chemical and physical reactions during cement *** this paper,early-age hydration kinetic equation is reversely extracted automatically from the observed time series of hydration degree of Portland cement using evolutionary computation method that combines gene expression programming and particle swarm optimization *** order to reduce the computing time,GPUs are used for acceleration in *** have shown that according to the extracted kinetic equation,simulation curve of early-age hydration is in good accordance with the observed experimental ***,this equation still has a good generalization ability even changing chemical composition,particle size and curing conditions.

关键词： Portland cement hydration kinetic equation reverse extraction gene expression programming particle swarm optimization

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Effective use of the spectral information in speech processing of cochlear implant

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Progress in Natural science:Materials International 2007年第3期17卷 334-339页

作者： GUAN Tian, GONG Qin and YE Datian ( Joint Research Centre for Biomedical Engineering, Department of Electronic Engineering, The Chinese university of Hong Kong, Hong Kong, china Research Centre of Biomedical Engineering, Graduate School at shenzhen, Tsinghua university, shenzhen 518055, china) [a]Joint Research Centre for Biomedical Engineering Department of Electronic Engineering The Chinese University of Hong Kong Hong Kong China [b]Research Centre of Biomedical Engineering Graduate School at Shenzhen Tsinghua University Shenzhen China

Based on the results of the acoustic research on Mandarin, two novel algorithms using the spectral information in speech processing of cochlear implants are purposed and certified effectively by the spectral information of tonal language in acoustic simulation experiments. We bring forward novel algorithms conveying the spectral information based on the choices of the frequency bands. These new algorithms can not only improve the speech recognition ability of cochlear implant users in the noisy environments but also reduce the complexity of computing and the memory occupied, and make it more suitable to be carried out in clinical practice.

关键词： cochlear implant speech signal processing signal processing.